基于贝叶斯网络的富水砂层深基坑渗漏动态风险分析

Dynamic risk analysis of deep foundation pit leakage in water-rich sand layer based on Bayesian network

针对富水砂层地区深基坑围护结构渗漏问题突出、危害严重的问题,为适应开挖过程中渗漏风险随时间变化情况并提高评价客观性,提出了基于贝叶斯网络的深基坑渗漏动态风险分析方法。以杭州富水砂层深基坑渗漏病害为背景,构建了涵盖地层、补给、结构和变形等因素的渗漏风险评价指标体系;运用贝叶斯网络及Leaky-Max假设构建静态贝叶斯网络模型,分析了渗漏概率的敏感性及渗漏损失的风险因素和指标。工程实例分析结果表明,采用该方法得到的富水砂层深基坑开挖过程渗漏的动态损失、渗漏概率和风险等级结果与工程实际情况一致,验证了方法的合理性,可用于富水砂层深基坑工程围护结构渗漏风险预测。

Aiming at the prominent and serious leakage problem of retaining structures of deep foundation pits in water-rich sand layers,a dynamic risk analysis method for deep foundation pit leakage based on the Bayesian network is proposed to adapt to the change of leakage risk over time during excavation and improve the objectivity of evaluation.Taking the leakage disease of deep foundation pits in water-rich sand layers in Hangzhou as the background,a risk analysis index system covering stratigraphy,supply,structure,and deformation was established.The static Bayesian network model was constructed using the Bayesian network and the Leaky-Max hypothesis to analyze the sensitivity of leakage risk probability and the risk factors as well as indices of loss.The results of engineering case analysis show that the dynamic loss,probability and risk level of leakage during the excavation of deep foundation pits in water-rich sand layers obtained by this method are consistent with the actual engineering situation,which verifies the rationality of the method that can be used to predict the leakage risk of retaining structures of deep foundation pits in water-rich sand layers.